Sending 50 KG of parts by air mail is too rich for most, and there is no change in surface service.

In addition, the last sentence indicates that the limitation on air service is expected to be lifted.
Probably after some actual or token toner bomb prevention program is put into place. They just have to figure out a way to inconvenience and harass packages to the same extent they do air travelers, and the public will feel safe again.

Japan Post Services Co. said it will stop accepting airmail packages bound for the United States weighing 453 grams (1 pound) or more starting Wednesday because airlines will stop such delivery at the request of U.S. aviation authorities as part of antiterrorism measures.

The postal services arm of Japan Post Holdings Co. handles 16 million letters and packages by air and sea to the U.S. annually, and "15 percent of that will be affected," a Japan Post spokesman said. That means about 200,000 packages a month will be affected.

The company said it will accept packages from senders that use a service enabling them to pay after delivery instead of beforehand, a service designated for regular customers, even if a package weighs 453 grams or more. The company will notify the public of any changes in the situation, the spokesman said.

The Transportation Security Administration of the U.S. has informed air carriers of the 453-gram rule, and carriers notified Japan Post Services, the spokesman said. The rule applies not only to packages from Japan but from other countries.

Packages containing explosives were found in Britain and Dubai on two cargo planes from Yemen bound for the U.S. in late October. The TSA heightened its aviation alert level since then.

The Japanese units of Fedex Corp., United Parcel Service of America Inc. and DHL International GmbH said they have no similar plans as Japan Post's. But DHL "will cooperate with the United States and other countries as they have raised (the) security level," spokeswoman Maho Takahashi said.

Overseas Courier Service Ltd. said it stopped accepting packages Friday to be delivered to the U.S., Latin America, Europe and Africa containing ink cartridges or toner cartridges weighing more than 450 grams.

There are not a lot of blog comments. Most are upset that they will not be able to get their anime books. A couple mail order vendors are upset. Others are saying that they are unaffected, because htey have a business account with the post office that will allow them to continue to ship heavier packages by airmail, because the restriction applies only to counter service by private individuals.

One of the more insightful comments pointed out that this restriction is taking place only in Japan, and only for packages shipped to the US. Canada, Europe, or any other destination is unaffected. US owned air planes fly to those countries, and carry mail to those countries, all of which allow over one pound packages.

Another insightful comment pointed out that 15.9 ounces of explosives is probably indistinguishable from 16.1 ounces of explosives in destructive capacity.

It does seem kind of strange that a Buddhist/Shinto, anti-nuclear/anti-war country might be the supposed sole origin of mail bombs.
And that we can continue to ship Priority Mail Flat Rate boxes up to 20 pounds from the US to Japan until the cows come home.

I kind of expected they would ban the sale of ink cartridges by mail, but that guy spamming my email address with ink cartridge solicitations must have a really really strong industry lobby in the government.
Or maybe the Japan Post just want to reduce their workload by 15% for the upcoming holiday season.

I've got people asking me if I received the boxes they mailed to me that were supposed to arrive by Christmas. And no boxes from anyone.
I don't know if everyone mailed their Christmas packages between November 16 and December 3 (during the air mail ban), or if I've just been preselected once again to have all my packages lost, run over, or confiscated as contraband.

Best bet:
Christmas arrives some time around the beginning of April, the same time the post office starts returning all the Christmas cards I mailed out in the second week of December...

I've got people asking me if I received the boxes they mailed to me that were supposed to arrive by Christmas. And no boxes from anyone.I don't know if everyone mailed their Christmas packages between November 16 and December 3 (during the air mail ban), or if I've just been preselected once again to have all my packages lost, run over, or confiscated as contraband.

Best bet:Christmas arrives some time around the beginning of April, the same time the post office starts returning all the Christmas cards I mailed out in the second week of December...

Could be that packages shipped during that time are still in limbo. Although from what I've heard, at the time, they were being sent back to the shipper (at least in Japan that was the case). Where were your packages coming from? I had a couple of packages that took an extremely long time to arrive - one from Canada and one from Jordan.

As far as I know, everything is back to normal - A package shipped from Japan on the 11th has already arrived at customs in Los Angeles and I should get it by the end of this week.